RE:BUILD - The Stranded Scientist
by JikanNoEiyu
Summary: A rewind of an old tale, of the Genius Scientist, thrown into a new world, and forced to embark on a new adventure with new friends. But is it all it seems to be?


**Kamen Rider Build: The Stranded Scientist  
Episode [sin^** **2** **(x) + cos^** **2** **(x) + e^** **(pi)i** **]**

 **Arc [1/2 + 1/4 + 1/8 + 1/16 + 1/32 + ...]: Introduction**

 _ **-**_ _ **エボルト**_ _ **:**_ _ **赤い星の駆逐艦**_ _ **-  
\- Eboruto: Akai Hoshi no Kuchiku-kan -  
\- Evolt: Destroyer of the Red Stars -**_

* * *

 **Sento:** Civil war has erupted between the three member nations of the fractured Japan, Touto, Hokuto, and Seito; the object they fight for is the mysterious artifact known as the Pandora's Box, which is rumored to contain an enormous amount of power within the vessel. However, the state of Japan is threatened by the uprising of the alien life form Evolt, the owner of the Pandora's Box, and the one pulling the strings behind the whole war.

 **Sento:** Kiryu Sento, Kamen Rider Build, rallies together with the remaining Kamen Riders to fight against the newly-risen Evolt, who not only has regained a power beyond what any of them are capable of standing against, but has also possessed Banjou Ryuga, Kamen Rider Cross-Z, and 'brother in blood'. However, during their fight, Evolt snatches the Pandora's Box and the sixty FullBottles, unlocking its full power: the Pandora Tower.

 **Sento:** As the fight enters what seems to be its final phase, the only Riders capable of fighting, Sento and Kazumi (Kamen Rider Grease), encounter Evolt in order to rescue Ryuga, and defeat the alien life form once and for all.

* * *

Multiple Hard Smash and Guardians laid waste to the streets of Touto, attacking everybody present in the area who had been strolling around. This wasn't just some random occurrence any more to the civilians; this was part of the ongoing war between Touto and Seito that was about to supposedly reach its final phase. And to be honest, the nation state was in complete chaos at this point; the leader, Himuro Taizan, had been killed by the recently-risen alien life form, Evolt, and the only heir to the leader, Himuro Gentoku, had not only been sacked out of Touto by his father, but unknowing to everyone, he believed that he was unfit for the role.

As the Smash and Guardians sent out by Seito continued attacking the city streets of Touto, a figure watched from above as they attacked; Evolt, who had been possessing Banjou Ryuga, and was currently snapping his fingers out of boredom, as he watched the chaos unfold in front of him, with a slight tint of joy in his eyes. He had to admit, as the destroyer of the stars, he found destruction to be an inner beauty within itself. And as Evolt would continue watching the carnage in front of him, Nanba Juzaburo, head of Nanba Heavy Industries, who had been disguised as the Prime Minister of Seito, Masakuni Mido (who had been killed by Evolt), began his announcement, a drone shot of him viewed on one of the buildings' wide screen.

 _"Finally, the day Seito conquers Touto has come. Let me declare victory once again."_

As he would hold up a tablet, it would show an emblem of Touto, before it burned away to show the emblem of Seito. As Evolt would laugh at that particular prospect, he would then hear two people running towards him, before he would then turn around. And as he turned around, he would then see Sento and Kazumi, who was running towards him, having already equipped their respective transformation belts. And as they stopped, they would then take out their respective transformation trinkets, Sento taking out the FullFull RabbitTank Bottle, and Kazumi taking out the Robot SclashJelly, before they would then activate them, twisting their caps and transforming into their respective forms, Build RabbitRabbit and Grease respectively.

 **[MAX HAZARD ON! RABBIT! RABBIT AND RABBIT! GATAGATA GOTTON! ZUTTAN ZUTTAN! ARE YOU READY? OVERFLOW! KURENAI NO SPEEDY JUMPER! RABBITRABBIT! YABEI! HAEI!]**

 **[ROBOT JELLY! TSUBURERU! NAGARERU! AFUREDERU! ROBOT IN GREASE! BURRAAAA!]**

"Henshin!" The armors would form around them, as Evolt would send out the Hard Smash and Guardians that had been protecting him (not that he had a need for them anyways). And as the creatures began to attack the two Riders, they would then take out their respective weapons, before beginning to attack them, Sento easily fending off against them and Kazumi not having such an easy fight as Sento due to his slightly lower Hazard Level.

 **[RABBIT! FULLBOTTLE BREAK!]**

They would then continue fighting against the creatures, as Evolt watched on. Then, Sento would then take out the Rabbit FullBottle, before shoving the Bottle into the FullBottle Buster's loading slot, as he would then ready a mini-finisher, before firing out a large ray of red energy, sending the two monsters he was fighting backwards, before they would be destroyed by Evolt, who would then punch them into oblivion, as he took out the Cobra and Rider System EvolBottles,

As Sento watched on, still shocked, the Evol-Driver would manifest itself on Evolt's waist, as he would then twist the caps, before inserting the two EvolBottles into his Driver, pulling on the crank and activating his first phase, as Nanba would then continue with his announcement. "Henshin."

 **[COBRA! RIDER SYSTEM! EVOLUTION! ARE YOU READY? COBRA! COBRA! EVOLCOBRA! FUHAHAHAHAHA!]**

 _"With Touto conquered, this is the dawn of the founding of a new unbeatable country." Utsumi would continue to pilot the drone as Nanba/Mido then stood firm, announcing, "We will be reborn, as a strong and powerful country."_

As the fight between Sento and Evolt began once again, he would use the Buster to try and fire multiple shots at Evolt. However, he would simply activate his Flash Step, dodging all of the shots, before he would then rapidly throw out punches at Sento, causing him to be sent backwards a little, before he would then regain motion, changing the Buster's setting from Blade Mode, which he had been using to defend against Evolt, to Gun Mode, before taking advantage of the Rabbit FullBottle that was still in the weapon, firing another red blast of energy at Evolt, that would send him flying back.

 **[RABBIT! FULLBOTTLE BREAK!]**

And he made sure to make the most of his fighting opportunity, as he would then dash behind Evolt, before elongating his arms, and becoming a living slingshot, sending Evolt flying in the opposite direction a second time, causing the planet destroyer to crash into one of the nearby buildings. And as Evolt would fall to the ground, Sento would then take out the FullFull Bottle, before shaking the Bottle once again, twisting the cap and activating its Tank Mode, before re-inserting the Bottle into the slots of the Build Driver and twisting the crank.

 **[TANK! TANK AND TANK! GATAGATA GOTTON! ZUTTAN ZUTTAN! ARE YOU READY? OVERFLOW! KOTETSU NO BLUE WARRIOR! TANKTANK! YABEI! TSUEI!]**

As his armor formed, it would then begin firing multiple bullets at Evolt which made him forced to hold his hands in front of him for cover, before transforming Sento into TankTank. Then, Sento continued his attack, by removing the Rabbit FullBottle from the Buster, and inserting the Spider FullBottle before preparing another one-Bottle attack, sending out multiple spider webs that would trap Evolt to the building he had crashed him earlier.

 **[SPIDER! FULLBOTTLE BREAK!]**

And as he would finish with his mini-finisher, he would prepare another one, as he took out the Spider FullBottle from the Buster, inserting the Dryer FullBottle into it, before preparing a giant red blast of energy, and firing it at Evolt, which would turn into a giant heat stream, beginning to slowly overheat the Evol-Driver system.

 **[DRYER! FULLBOTTLE BREAK!]**

Evolt would take the brunt of the attack, unable to dodge, as he then realized, "You've beaten Phase 1 already?" And as he continued taking the full brunt, he would struggle against the webs and the heat, stating, "Then how about this?!" He would manage to get his right hand free, as he took out the Dragon EvolBottle, replacing the Cobra EvolBottle for it, as he began to pull the crank once again. The armor forming around him would help to break the webs, and dissipate the heat around him, as he transformed into Phase 2, retaliating with his own attack.

 **[DRAGON! RIDER SYSTEM! EVOLUTION! ARE YOU READY? DRAGON! DRAGON! EVOLDRAGON! FUHAHAHAHAHA!]**

Evolt would then land on the ground, utilizing his Flash Step to dash towards Sento, before rapidly sending out punches at him, with Sento unable to dodge due to the sheer strength of the form. Evolt would continue sending out punches at him, forcing Sento to slowly retreat backwards, as he would parry the blows to the best of his ability. Meanwhile, Kazumi was still facing off against the two creatures from earlier, still unable to defeat them due to his strength. As he would parry their blows, Nanba once again continued.

 _"This country will take on the entire world. Let's show them the true power of 'Made in Japan'."_

As Sento continued to struggle to fight the planet destroyer, Evolt would then summon the Beat Closer, being able to utilize it due to the Dragon EvolBottle, as he repeatedly slashed at Sento, sending him flying backwards. As Sento tried to catch the blade that Evolt had thrown, he would hear the announcement made by Nanba. Evolt would then comment, "Now he's waging a war against the world? I was right." Then, he would pull the end of the weapon once, initiating a mini-finisher that would send Sento flying backwards.

 **[HIT PARADE! SMASH HIT!]**

As Sento fell to the ground, clearly drained of his stamina, Evolt would finish his attack, before mentioning, "There's no limit to humanity's greed. Or foolishness for that matter." Sento would then force himself to stand up, before gritting his teeth and exclaiming, "That's not true! We'll put an end to this useless war!" Then, he would take out the new FullBottle he had created; the Pandora Panel Bottle that he had made the previous night. As he was about to utilize its dangerous power, nearly inserting it into the Build Driver, he would then freeze, before he would stare at it, remembering what had happened minutes before he charged into battle. Misora's tearful expression, it was crystal clear in his brain...

 _"So you're prepared to die? For Banjou? For Touto?" Sento only slightly nodded to Misora's question, before she would let go of her grip on him. "Why don't you value yourself more? If something happened to you, what would we do?! Think of the people who are left behind! Like Banjou, Sawa-san, like me! If I don't stop you now, I'll regret it for the rest of my life!" She would freeze, before holding firmly onto Sento's sleeve once again, stating, "It'd be so painful."_

 _Sento then stated, "I sowed the seeds of this war. The Build Driver. The FullBottles. The Sclash Driver. The SclashJellies." Misora then looked up at him, her eyes on the verge of tears, as she then asked, "Is that why you're taking responsibility? That's just sheer selfishness!" She would snatch the Pandora Panel FullBottle away from him, before turning around. Then, Sento would state, "I'm the only one who can stop this war... I have no choice, but to fight." Misora, about to cry, would then ask, "Why? Why can't I get through to you?"_

 _She began to cry, as Sento would hug her, comforting her to the best of his ability. Patting her head, Sento would then mention, "You have. Don't worry. I'll definitely come back." Then, he would take the FullBottle from her, before he would leave, about to charge into battle to rescue Ryuga._

Sento would then state to himself, "I'm sorry... I have to protect everyone and restore peace. Nothing is more important than that..." As Sento looked back up, he would regain his momentum, before taking out the FullFull Bottle, and shoving the Pandora Panel Bottle into the Driver, as the Panel would then begin coursing a rainbow of colors, awaiting transformation. And then, he began to pull on the crank.

As he pulled on the crank of the Driver, the effects of the FullBottle began to take control of him, causing multiple blue jolts of electricity to begin coursing through the Build Driver, and subsequently into his armor, causing Sento to scream in pain. Evolt merely stared at Sento's transformation as he continued pulling the crank, the jolts of electricity continuing to take control of his body. However, gaining his resolve, Sento painfully responded, "Build... Up!" as he readied himself for his next move. Unleashing all of the built-up electricity that had been coursing through his body, the electricity would be unleashed all around Sento, causing miniature explosions, as Evolt slashed the ones heading in his direction using the Beat Closer.

 **[SCRAP FINISH!]**

"This is..." Evolt noticed something off with Sento's upgraded transformation, as he stared onto Sento, who had been walking towards him, seemingly rejuvenated as if his previous attacks on Sento weren't having any effect on him. As Kazumi would execute his finisher, finally destroying the two creatures, Evolt would then send the blade down onto Sento's shoulder, letting out tiny sparks; however, Sento didn't budge, causing Evolt to suddenly stop his attack in surprise, also gaining the attention of Kazumi, who had dashed to the site of Sento and Evolt's fight.

And on command, Sento then punched Evolt with a force hard enough to land him in the nearby body of water, along with his blade. Sento merely stared at Evolt, a newfound strength showing itself, as Kazumi could only ask in shock to himself, "What's going on?" As Evolt crawled out of the small body of water, he'd merely comment on Sento's newfound strength, "Hazard Level 6! So you've finally surpassed human limits?" As he sat up, gaining his composure back, he'd merely continue his statement, "Well done, Sento. So you're another one of those foolish humans."

As Sento stared on, he simply asked regarding Evolt's sudden statement, "What do you mean?" Evolt then stood up, facing in Sento's direction as he then asked, "Why do you think I caused this war?" He stared at Sento maliciously as he then replied to his own question, "So I could use you to restore my own power!" As Sento gasped, on the road to realizing the truth about something far more malicious than he imagined, Evolt took out the incomplete Evol-Trigger, holding it in his left hand, as he then continued his talk, "For a human, there's a limit to how much of the energy in this that can be used." Walking towards Sento, he would then continue, "That's why I took advantage of the power of science. If a war began, you'd have no choice but to strengthen the Rider System, whether you liked it or not."

Sento then realized the truth behind Evolt's continuous asking of him upgrading, even before he knew of his true identity, and he stared at his own armor, reminiscing on the major upgrades the Rider System had undergone ever since he first gained many months prior to the present.

 _The FullBottle purifications that he, Soichi and Misora had been doing before the reveal of Soichi's true identity as Blook Stalk and subsequently Evolt, in particular the Touto set of FullBottles; Rabbit, Tank, Gorilla, Diamond, Taka, Gatling, Ninja, Comic, Panda, Rocket, Harinezumi, Shoubousha, Lion, Soujiki, Dragon, Lock, Kaizoku, Densha, Octopus, Light, Doctor, Game._

 _ **[RABBIT! TANK! BEST MATCH! ARE YOU READY? HAGANE NO MOONSAULT! RABBITTANK! YEAH!]**_

 _The creation of the RabbitTank Sparkling FullBottle, utilizing the RabbitTank Best Match and a mysterious bottle that contained the essence of the Pandora's Box, and subsequently its first usage against Blood Stalk in the alleyway he had been 'found' at by Evolt._

 _ **[RABBITTANK SPARKLING! ARE YOU READY? SHUWATTO HAJIKERU! RABBITTANK SPARKLING! YEA-YEAH!]**_

 _The Hazard Trigger that Evolt had given him to defeat the Three Crows, which had come with massive strength, and berserker-murderer effects, and subsequently his first fight with it against the multiple Hard Smash that Hokuto's prime minister, Yoshiko Tajimi, had sent at him and Banjo back when Touto and Hokuto were at war with each other._

 _ **[RABBIT! TANK! SUPER BEST MATCH! GATAGATA GOTTON! ZUTTAN ZUTTAN! ARE YOU READY? UNCONTROLLED SWITCH! BLACK HAZARD! YABEI!]**_

 _The FullFull RabbitTank Bottle that he had created to overcome the berserker effects of the Hazard Forms, the speedy RabbitRabbit Form and its first usage during the 3-on-3 battle with Seito, the strong TankTank Form and its first usage to defeat Rogue during the second battle with him, which ensured Touto's 'victory' in the war._

 _ **[MAX HAZARD ON! RABBIT! RABBIT AND RABBIT! GATAGATA GOTTON! ZUTTAN ZUTTAN! ARE YOU READY? OVERFLOW! KURENAI NO SPEEDY JUMPER! RABBITRABBIT! YABEI! HAEI!]**_

 _ **[MAX HAZARD ON! TANK! TANK AND TANK! GATAGATA GOTTON! ZUTTAN ZUTTAN! ARE YOU READY? OVERFLOW! KOTETSU NO BLUE WARRIOR! TANKTANK! YABEI! TSUEI!]**_

 _And lastly the Pandora Panel FullBottle that he was currently using._

 _ **[ARE YOU READY?]**_

He could hear the transformation sounds accompanying each memory that he had of the powers that he had created, either as Sento, or as Takumi. Evolt then continued with his speech, "And with this power, you would become the ultimate Kamen Rider. That's what Project Build really was about!" As Sento stared at Evolt's grinning form, anger and hatred slowly seeping its way into his mind, he then barked back, "You caused a war for _that_?! What bullshit!" Dashing towards him, Sento would try to punch him with the newfound strength that he still supposedly had, only to be met with sparks forming from Sento punching Evolt's face, before he then flash stepped out of the way, punching Sento in the armour at the gut, and causing a hole to form in the armor, Evolt's hand inside it. Evolt merely taunted Sento's failure, "Too late! Everything went as planned!"

Sento stared at Evolt, unable to anything, the feeling of losing his own life force present. Kazumi, on the other hand, was horrified at the scene unfolding in front of him, and he dashed towards Sento and Evolt, screaming, "Evolt's fist is in Build!" As Evolt began to absorb the power of both Sento and Build, he'd then state, "I shall take Build, who has surpassed human limits and become complete!" Absorbing the power of Build, multiple surges of energy would fill Evolt's armor, and with that, suddenly, Ryuga's body would fall backwards, Evolt finally no longer possessing him. As Sento saw what had happened then, he simply grinned, painfully laughing, as he then stated, "I was waiting for that."

Immediately, Sento would then pull the crank of the Build Driver once again, as the Pandora Panel continued to course through a rainbow of colors, his Hazard Level rising and Evolt looking on in confusion. Sento would then state, "Measure my Hazard Level." Evolt, hand still absorbing Build's power, retorted in shock, "What?! 6.1! 6.2! 6.3! Impossible... it keeps going up!" A large surge of energy would then be released from Sento's armor, causing Evolt to reel in pain, and Kazumi to even be pushed backwards. Sento then continued pulling the crank, as he stated, "Thanks to Dad's experimental data, I saw through your plan!"

 _He then remembered Dad's research plan, intent on creating a device that could channel the full power of Pandora's Box to help him destroy Evolt once and for all; data that Evolt had deleted at one point to prevent anybody from discovering a method of destroying him._

Sento grinned, staring at Ryuga's unconscious body as he continued to pull the crank. "I pretended to fall into your trap so I could save Banjou!" Evolt, suddenly shocked at something he hadn't expected in the slightest, then suddenly asked, "Do you know what raising your Hazard Level so quickly can do?!" Sento, finally fully at his resolve, then shouted as his free hand then latched onto Evolt's hand, "Yeah! I'll perish with you!" Sento's rapidly rising Hazard Level caused his armor to begin dissipating, and he stared into Evolt, screaming, "This is the end, Evolt!" Evolt's armor too began to dissipate, asked in anger, "A human, deceive me?! Bullshit!" He would then grab Sento's other hand, the one that he had been using to pull the crank, but Sento would grab him with his free hand, latching onto him, as a bright explosion took place, fog surrounding the explosion soon after, as Kazumi shielding himself from the explosion.

As the mist dissipated, all that was left was Ryuga's unconscious body, the Evol-Driver and the incomplete Evol-Trigger that Evolt had been using, and Sento's Build Driver, Hazard Trigger and FullFull RabbitTank Bottle. However, neither Sento or Evolt were present, which only meant one thing; Sento had truly defeated Evolt, but at a heavy cost... Sento had truly committed a suicide attack. And that was the end of the legend of Kamen Rider Build. A hero that went down in history in order to protect the love and peace that he idolized.

 _...or was it? Was it the end, or was it just the beginning of something more?_

* * *

 **?:** Now, in The Stranded Scientist, a legend is brought back to life, and discovers that what he's in for is far bigger than anything he's ever imagined.

* * *

A pair of eyes suddenly jolted open, as a huge gasp was immediately let out. Kiryu Sento, the scientist who was presumed to be dead, after defeating Evolt, suddenly had his eyes jolted open. He woke up as if he had just woken up from a nightmare, as he immediately tried to focus in on his surroundings. As he was about to get up, and figure out what was going on, he then noticed something; why were there forest trees in his view? He clearly would have seen a wall, if he was waking up, unless he was actually fighting Evolt- oh wait... he did.

And he remembered clearly what he had done in order to have defeated him. He remembered the Pandora Panel FullBottle, he remembered encountering Evolt with Kazumi, he remembered what Misora had ranted at him the previous day... and he remembered his suicide attack. But if he had actually somehow come back to life, why were there forest trees in his view once again? He would then get up, as he noticed a glass shard on the floor near him. Still confused at his presence in a forest of all places, he would check the shard to see if he was okay.

And that was when something immediately felt off. As he would check himself in the mirror, he would then realize something was horribly wrong with his body. And in his head, he could only think of one thing. 'Why does my body look and feel like a seventeen-year-old?! This isn't good!' He would panic slightly, as he forced himself to put that aside for the time being. Figuring out where he was is more important than trying to figure out why he looks like a seventeen-year-old.

And as he looked around him, he would wonder why he was in a forest to even begin with. To add to that, the emerald green hue the trees had wasn't the same as the ones he had seen back in Touto; it felt like he was in one of those games that pink and green Rider would play, Emu if he wasn't mistaken. He would then notice a giant building in the far distance, high above the trees, and he decided that heading in that direction was the better thing to do at this point.

Even if he had to admit that the tower didn't look like anything from Touto at all. Was he in somewhere that wasn't Touto?

However, as he was to head off in the direction of the tower, he would then hear wolf-like growls coming from the bushes and trees behind him, which immediately freaked him out. Searching for a weapon to defend himself, he then noticed the Build Driver on the floor, something he oddly enough didn't notice the first time. As he would then pick up, he would then notice four FullBottles on the floor as well, which was something that immediately caught by surprise.

And immediately, he would wonder, 'Where are the other FullBottles?!' But as he rushed to pick up the Driver and the FullBottles – Lion, Kaizoku, Gatling, Light – he then found some EmptyBottles, as he picked them up; maybe they would be useful in taking whatever essence he could find (he could get more Bottles this way?); then he also found the Build Phone, which he knew would eventually come in handy; and he also then noticed the Drill Crusher, which he immediately grabbed after then noticing something even more eerie; red eyes opening from the same trees and bushes from earlier. And that was when creatures started to emerge from the bushes. Black wolf-like creatures whose eyes glowed red, and aura signaled an intent to kill. As Sento held the Drill Crusher in his hand, the wolves would charge at him, attacking him almost instantly. And what Sento did was to, somehow, adeptly wield the weapon, swinging it at the wolves and hitting most of them.

It felt as if he somehow mastered it, something he was pretty sure he normally wasn't adept at when he wasn't transformed. And then suddenly, he could feel his eyes glow a tinge of red and blue, as he would then jump to avoid one of the wolf creatures. Immediately, his jump height was suddenly increased, and he would squeak in surprise. This wasn't something he wasn't expecting.

And he fell down, and landed perfectly. As Sento formed like those superhero poses, he would squeak in surprise even more, before dodging the wolves and attacking again. Deciding to transform immediately to settle this (he feared this weird thing he had going on would wear out and potentially cause his deaths), he grabbed the Build Driver, and equipped it instantly, causing multiple quantum physics equations to form, as they would hit the charging wolves, sending them flying back and causing them to leak a little bit of shadow.

And as Sento realized they weren't the normal type of wolves that he was acquainted with, he took out the Kaizoku and Gatling FullBottles, shaking them, before then twisting the caps of the Bottles, and inserting them into their respective slots in the Driver, as the emblems of a light blue skull with crossbones, and a gray gatling gun formed.

 **[KAIZOKU! GATLING!]**

Continuing to slash at the wolves that continuously charged towards him, he would then pull on the crank of the Driver, as the Build Snap Ride Builder began to form around him, the tubes beginning to fill with azure blue, and gray liquid respectively. And as they fully filled, the Kaizoku and Gatling HalfBodies formed on the Snap Ride Builder, as Sento readied himself, the belt awaiting permission to initiate the transformation.

 **[ARE YOU READY?]**

Entering his transformation pose, he then shouted, "Henshin!" And, as the belt gave permission for the transformation to take place, the HalfBodies locked to the tubes of the Snap Ride Builder who unlock, before being pulled towards him, the two halves locking together and forming the Build Armor, before multiple vents of Nebula Gas would be released from the transformation, and the Trial Form jingle would play, as the armor fully formed. KaizokuGatling, a Trial Form he had interestingly used once, even if it wasn't in the best of situations.

 **[HAWK GATLINGER!]**

And on instinct, as Sento readied himself, focusing on the heat of the battle and deciding to skip his post-transformation catchphrase, as he would then grab the weapon that had been summoned in front of him, before beginning to fire away at the Grimm, sending some of them flying away backwards as they continued to leak the same shadow-like substance they had been doing earlier. And as they were sent backwards, they would somehow manage to charge at him with precise speed, such that they'd manage to land a good couple of hits on Sento that would send him a little ways backwards. Changing the Drill Crusher to Gun Mode for good measure, he would then dual-wield the two weapons as he continued to fire away at the wolves, sending them backwards once again. And as he finished firing them out, he took out the Light FullBottle, before shaking it and twisting the cap.

And he prepared a finisher to hopefully finish them. He didn't have much time on his hands at the moment, and he needed to get out of the forest as fast as possible.

 **[LIGHT! READY, GO! VOLTECH BREAK!]**

As the weapon fully charged up, he would then fire out a large blast of light, that would not only blind the wolves, but also send out multiple bulb-like projectiles that would hit the wolves, which would also cause them to fall to the ground, as they seemed to be... fading to dust? Confused, Sento decided that further testing was required, as he took out two EmptyBottles to contain the essences of the wolves.

Preparing two in case the essence was not enough, he found himself surprised that both Bottles would absorb the essences of the 'wolves', as they turned into two different colored Bottles, one blue, and the other... black? And the black one was emanating a very eerie aura... Sento was both curious and scared at this point in time. But he decided that he'd think about it later, as he took out the Light FullBottle, storing it along with the two new SmashBottles, as he took out the Build Phone. Deciding to stay transformed just in case, he decided to head to the tower he had seen via the Machine Builder. And taking out the Lion FullBottle, he would shake it and twist its cap, before shoving it into the slot on the Phone, and pressing the Bike application.

 **[BUILD CHANGE!]**

As the Machine Builder formed, Sento would then notice the presence of the Bike FullBottle attached to a slot on the GUI display, as he would take it out, pocketing the Bottle. 'Okay, so that makes it five,' he thought to himself, as he would take a seat on the rider's seat. Then, he would rev up the engine, only to realize that it wasn't really such a good idea; it IS a forest after all.

He sighed. At least he found another FullBottle. So yeah, that's good.

As he changed the Machine Builder back into the Build Phone, he would take out the Lion FullBottle, before pocketing it and making his way through the forest, keeping the Drill Crusher at the ready, with the two L letter FullBottles even more on the ready. And as he began his trek through the forest, he found himself thinking of the fate of his world, or rather, the fate of Touto, Seito and Hokuto.

Even if he had defeated Evolt, there was no possible road that could connect the three nation states together, since even the Sky Road only connected Touto and Hokuto to an extent. Even so, the only people capable of potentially altering the Skywalls from his knowledge were Ryuga, through his alien DNA, and Misora, through Vernage. Even then, Vernage's power was fading, and Ryuga doesn't really know how to use such powers. Then again, there was also the Pandora Tower, and who knows if it's possible to undo the megalith out of existence.

And that was even if Evolt had been killed. And even then, he knew that Evolt definitely wasn't alone, that there were other members of his species out there. And he remembered Kazumi's conversation with Vernage...

 _The three remaining Kamen Riders had been saved from the brink of death by Vernage's powers, which was not only able to prevent the immediate destruction of the Earth, but also allowed for the powers of the Pandora's Box to be drained, delaying Evolt's plan even further. But the Pandora Tower was already completed anyways, and if Evolt was to get his hands on the essence once more._

 _Sento stood in the lab under nascita, as he walked towards the drained Pandora's Box, asking to himself, "So just what WAS the energy in the Pandora's Box? Why build the Pandora Tower to begin with?" And then, Vernage showed herself, activating Misora's golden bangle, before she began speaking, "The tower of destruction." That was enough for the three Riders to turn towards the former queen of Mars in shock. She then continued, "Our planet was destroyed when that tower was completed." She could feel flashbacks of the event happening, when the Pandora Tower was created, a black hole forming over it and wiping out all of Mars. She could remember her final confrontation with Evolt._

 _"A strange void above the tower sucked everything into it." And Kazumi would then walk towards her, before asking, "Just who the hell is Evolt then?" She would then respond, stating, "A lifeform of the Blood Tribe, an alien civilization unknown to Earth, He was able to destroy Mars, all on his own..." The three Riders were caught by shock, as Vernage narrated her final moments on Mars. "As the only survivor remaining, I became the martyr of my civilization. I was prepared to give my life to defeat him. I managed to damage his Driver, and I separated his soul and body, but he used the bloody box to store his energy."_

 _A spark of realization would trigger in the three Riders, as Gentoku stated whilst looking at the Box, "So the Pandora's Box belonged to Evolt this whole time?!" And as Vernage de-possessed Misora, her last line was, "Evolt must never be allowed under any circumstances, to regain his complete form..."_

It feared him. The thought of the Pandora Tower forming its black hole, and destroying what was left of Japan, and the rest of the world. This world might have heard of the legend of the Kamen Riders before, ever since a fateful day in 1971 from what he had read a while ago, but what good were they against a black hole? He merely could cling onto the possibility that Earth would be in safe hands, and that a potential peaceful future could come to reality...

But then, he remembered that Evolt's species wasn't the only problem that could ever arise; there was also still Seito after all. Taken over by Juzaburo Nanba, he had disguised himself as Seito's former Prime Minister, and had managed to trick Japan into thinking such. He clearly had the ability to summon the Guardians whenever he wanted, and Sento knew that a few well-timed attacks could potentially drop nascita for good. Then, there was the Kaiser System, utilized by the Washio Brothers. Thankfully, in the current state, the three other Riders were capable of taking them on if they needed to.

But then, there was also Utsumi, the wild card in all of this. He was the reason Kazumi and Gentoku had their Sclash Drivers to begin with, and he was also the reason the Kaiser System still exists, in the form of the Nebulasteam Gun, or so he calls it. There's no telling that he might get his hands on a Build Driver, or worse, the Evol-Driver, and make it his own...

But his thoughts were immediately thrown aside, when he found the tower he had been walking in the direction of, which immediately caught him by surprise. Was he really thinking for that long?! That's got to be at least thirty minutes! And the tower isn't just one tower! It apparently was part of a larger building which looked a lot like an academy! And then, Sento immediately noticed something, or rather someone, that had caught his eye.

As he de-transformed, taking out the FullBottles he had been using, the Nebula Gas dissipating around him, he noticed two individuals walking towards him, as if they had been hurriedly rushed here. The first man was wearing a shade of green, wore a pair of glasses, and seemed to be holding a mug, presumably filled with something. The other one, a woman, wearing what seemed to be a teacher's uniform, had a purple cloak of sorts on her back, and carried a weird device that looked like a holographic phone.

And that was when Sento asked, "Who are you two?"

* * *

 **-** **次回は** **,** **仮面ライダービルド** **! -  
** _ **\- Jikai wa, Kamen Raidā Birudo! -**_ **  
** _ **\- Next time on Kamen Rider Build! -**_

 _The tales of a scientist in a new body about to embark on a new adventure in a new world, a headmaster and headmistress with noble yet suspiciously odd intentions, a hero who burns brighter and brighter with the eyes of a dragon, and a pair of sisters whose personalities are starkly different!_

 _Tune in, for Episode [sqrt(9) – 1!] of Kamen Rider Build: The Stranded Scientist!_


End file.
